It's working! and a couple questions

So thanks first of all to everyone that helped me get this thing running! It took me a bit of time in off hours, but finally everything's working nicely and it's printing parts! So again, thanks so much for everyone that helped especially from the arduino mega area!

So my questions now: I'm having a really tough time getting a smooth outer wall particularly on taller parts. I see a few other people have had this before. I'm attaching a photo of what I mean. I'm wondering if anyone has seen a condition like this and how they resolved it. I've tried quite a few things changing extruder settings for higher and lower amounts, changing thickness of layers up and down, lowering overall print speed, etc. What it looks like to me is that a chunk of material gets stuck on the head and pulled along with the layer. Any thoughts on preventing this? Do I have a setting incorrect somewhere?

Machine's an ultimachine mendel, software: RepSnapper, material: PLA

If you are relying on the built-in slicing in RepSnapper, you are going to need to dive into Skeinforge to fix this.

Other things to check are that the belts are good and tight. The more slack in the belts, the more backlash when reversing direction. Also look at the belt gears and make sure there is no runout (off center wobble). This too can lead to inconsistent results in walls.

Maybe your Z-axis leadscrews are pulling the X-axis around? They may be rotating eccentrically.